Re: [libvirt] [PATCH] qemu: check for kvm availability before starting kvm guests

This *kind of* addresses: https://bugzilla.redhat.com/show_bug.cgi?id=772395 (it doesn't eliminate the failure to start, but causes libvirt to give a better idea about the cause of the failure). If a guest uses a kvm emulator (e.g. /usr/bin/qemu-kvm) and the guest is started when kvm isn't available (either because virtualization is unavailable / has been disabled in the BIOS, or the kvm modules haven't been loaded for some reason), a semi-cryptic error message is logged: libvirtError: internal error Child process (LC_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin /usr/bin/qemu-kvm -device ? -device pci-assign,? -device virtio-blk-pci,? -device virtio-net-pci,?) status unexpected: exit status 1 This patch notices at process start that a guest needs kvm, and checks for the presence of /dev/kvm (a reasonable indicator that kvm is available) before trying to execute the qemu binary. If kvm isn't available, a more useful (too verbose??) error is logged.

+ if (vm->def->virtType == VIR_DOMAIN_VIRT_KVM) { + VIR_DEBUG("Checking for KVM availability"); + if (access("/dev/kvm", F_OK) != 0) { + qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("Domain requires KVM, but it is not available. " + "Check that virtualization is enabled in the host BIOS, " + "and host configuration is setup to load the kvm modules.")); + goto cleanup; + } + }